http://mactkg.hateblo.jp/entry/2015/07/19/121031

pg_jack_test.pde

class Jack {
  PGraphics g_local, g_global;

  Jack() {
    g_local = createGraphics(width, height);
  }

  void begin() {
    g_local.beginDraw();
    g_global = g;
    g = g_local;
  }

  void end() {
    g_local = g;
    g = g_global;
    g_local.endDraw();
  }

  void draw(float x, float y) {
    image(g_local, x, y);
  }
}

Jack jack;

void setup() {
  size(800, 400);
  jack = new Jack();
}

void draw() {
  background(0);
  
  jack.begin();
  background(128);
  fill(255);
  ellipse(width/2, height/2, 50, 50);
  jack.end();
  
  jack.draw(frameCount%width, frameCount%height);
}